[Acute mesenteric vascular occlusion: pathophysiology, clinical stages, diagnosis].

Advanced age and cardiovascular diseases cause of SMA occlusion. Shock is triggered and maintained by bowel ischemia. Since lactate is the end product of anaerobic glycolysis, lactacidosis is a valuable clinical parameter. Lactate values above 4-5 mmol/l are conclusive evidence in the presence of symptoms of acute SMA occlusion. Chance of survival are poor in stages II and III with advanced shock and non reversible gangrene. Revascularisation of the SMA combined with adequate bowel resection reduces the production of toxic and lethal substances in the intestinal mucosa, thus increasing the chance of survival. Determination of serum lactate should be an integral part of the diagnostic procedure and the close followup for it is both an adequate index of the grade of intestinal ischemia and a means of assessing whether a second-look is warranted.